FR2523018A1 - GRINDING GRINDING DEVICE - Google Patents

Abstract

THE INVENTION CONCERNS A GRINDING DEVICE FOR THE FINISHING OF A VALVE SEAT OR A SEAL FACE, BICONE BUSHING OF AN INJECTOR IN PARTICULAR, INCLUDING A WHEEL-HOLDER 4 MOUNTED WITH A SUPPORT AND GUIDING ELEMENT 5 , WITH INTERMEDIATE CLEARANCE, IN A FINISHED PART 2 BORE. THE DIAMETER OF THE SUPPORT AND GUIDING ELEMENT, WHICH CONSTITUTES A ROD, IS LESS THAN THAT OF THE SPINDLE; AT ITS FREE END 38, THIS ROD SUPPORTS WHEEL 6, THE OTHER END BEING CONNECTED TO THE WIDELY HIGHER DIAMETER PIN. THE WHEEL-HOLDER SPINDLE, EXTERNAL TO THE BORE OF THE PART, IS EXTREMELY STABLE AND MASSIVE. THE FIXING OF THE ROD BY THIS HIGH STABILITY SPINDLE PROVIDES PERFECT GUIDANCE AND SUPPORT OF PART 1, EVEN FOR EXTREMELY LOW BALE DIAMETERS.

Description

was 3 Oi 8

Rectification device.

  The present invention relates to a device for rectification

  tion for the finishing of a valve seat or of a seal face, notably a bicone ring of an injector, comprising a spindle connected to a grinding wheel, as well as a support and guide element, eccentric in a finished bore of the part during the machining operation and integral with the

grinding wheel spindle.

  On a known device of this kind (DE-OS 29 12 814), the

  the support and guide element consists of a cylindrical sleeve which envelops the grinding spindle in the

  central bore area of part A one of its ex-

  hoppers, the spindle supports the grinding wheel adapted to the slope of the valve contact surface For relatively small central bore parts, whose diameter is for example equal to or less than 6 mm, this known rectification device no longer responds with high demands

  machining precision This drawback is due to the sta-

insufficient bility of this assembly.

  For injection pump injectors for example, it is more and more often essential to manufacture

  parts with very small bore diameter.

  The present invention aims to create a rectification device.

  cation of this type, which also makes it possible to obtain a high machining precision on bores of very small diameter. According to an essential characteristic of the invention, the e-

  the support and guide element consists of a ti-

  ge of diameter smaller than that of the grinding spindle, this rod supporting the grinding wheel at its free end and

  being longer than the bore of the part, such a

  that the spindle is outside this same bore

in working position.

  According to the invention, the grinding wheel spindle being external to the workpiece, its diameter can be much greater than that of the bore, and its execution can therefore be extremely stable and massive. The fixing of the rod on the grinding wheel spindle further improves the maintenance and guidance of

  the part, even with a very small diameter This assembly con-

  form of the invention also allows the use of bro-

  traditional grinding wheel carriers, extremely precise and fast, for example with hydrostatic or aerostatic carrying and a rotation speed of 60,000 to 000 rpm The rigid and solid design of the spindle ensures very high machining precision, responding to the

higher requirements.

  Other characteristics of the present invention, given

  in claims 2 to 15, will be better understood

  using the detailed description below and the drawings

attached, which represent:

  Figure 1: an axial section of part of the device

  shape of the invention, Figure 2: a top view of part of a second shape

  for constructing a device in accordance with the invention

  tion, Figure 3: an axial section of a part of the device according to the invention, in another form of construction. Figure 4: a section along the line IV-IV of Figure 3. Figure l shows a rectification device with the part 1 mounted, which has a finished central bore 2

  by honing and a valve seat 3 concentric with this

  wise, and should be rectified on the device For the u

  tipping of the seat 3, the device has a rod 5, which supports at its front end 38 a grinding wheel 6 adapted to the

  slope of the surface 3 The rod 5 is integral with a bro-

  che grinding wheel holder 4 It is simply mounted on its ex-

  end 26 external to bore 2 in a corresponding bore

  dant 27 of the spindle 4 In order to improve its resistance, the rod 5 is of a massive design, entirely composed

  preferably made of hard metal, and present throughout its length

  on the same circular section Its diameter is small

  slightly lower than that of central bore 2, but much weaker than that of spindle 4 The latter is a multiple of that of the tick, at least double the

  quadruple in the construction example This diameter im-

  bearing gives pin 4 a particular resistance

  rement high, which guarantees the maintenance of the rod 5 in the spindle even for the machining of seats of very small surface, and therefore an extremely precise machining of this surface. For machining the seat 3, the part 1 is brought to the

  rod 5 manually, or preferably by means of a device

  positive known (not shown) The part is then

  fully guided and held on the rod 5 in its

wise finished.

  In order to ensure that the piece 1 is held and guided without play, a drive element 9, represented by a

  roller, attack the periphery 8 of the piece I concentri-

  than at the central bore 2 Part 1 is therefore compressed

  against the lateral face 7 of the rod 5 and driven in rotation

  tion Via a known device (not re-

  shown), hydrostatic cylinder / piston mounting for example-

  full, the drive roller 9 is moved towards the part 1 (arrow-

  che 10) by a predefined force, preferably with progressive adjustment, and driven in rotation in the direction of the arrow 11 by a drive (also not shown), an oil motor for example The part 1 therefore rotates in the opposite direction (arrow 13) of pin 4 (arrow 12), with

  a lower speed, however, 200 to 3000 rpm per e-

  xample. To give part 1 an axial feed movement

  (arrow 25), the drive roller 9 is connected to a drive

  already known, which allows a pre-

  cise of the grinding wheel 6 on the seat 3 of the part 1 and a re-

  gradual adjustment of the grinding pressure.

  In another form of construction (FIG. 2), the axis 28 of the drive roller 9 has an acute predefined angle 15, preferably 20 to 5 e, with the axis of the part 29, so that a axial component is superimposed on the rotational movement of the drive roller 9 a, in the direction of the part 1 (arrow 24) The grinding pressure

  can be adjusted by adjusting and changing the angle 15.

  Motor rollers 9 or 9 a can be replaced by

  a belt drive designed accordingly.

  positive shown in Figures 1 and 2 also have a cooling system, the only nozzle 18 is illustrated (Figure 1), through which a refrigerant and lubricant under high pressure is

  introduced into the rectification zone 16 of the part 1.

  The nozzle 18 being aligned with the orifice 17 of the part, at

  a slight distance from the latter, the jet injected under high

  the pressure by the nozzle 18 is directly oriented on the

rectification area 16.

  As a result of the high pressure, the coolant and lubricant is pushed into the crescent-shaped gap 19, located upstream of the cutting zone 16 in the direction of advance 25, and separating the central bore 2 of the side face 7 In this gap 19, the coolant and

  lubricant forms a lubricating film, which constitutes a

  hydrostatic stage between rod 5 and part 1 This holder

  tage is very precise and considerably reduces the friction

  between rod 5 and the part The refrigerant and

  lubricant comes out on the front face 30 of the part 1 orien-

  tee towards the grinding wheel spindle to be directed, by means of a cover 20 and a collector 21,

to return line 22.

  The collector 21 has the form of a flat box, of section

  practically circular, having two passage openings

  coaxial ge 31 and 32 on the opposite side walls in the form of a disc The opposite ends 33 and 34 of the part 1 and of the spindle 4 penetrate into these orifices 31 and 32 The cover 20, circular, bears on the face

  corresponding front 35 of the end of the spindle 34.

  The cover having a curved edge 36 external to the spindle 4 and a diameter very slightly smaller than that of the collector 21, the tightness of the spindle 4 relative to

  to the coolant and lubricant is perfectly assu

  The return line 22, which is located in the pro-

  along the outer cylindrical wall 37 of the manifold 21, is preferably designed in one piece with the latter. Furthermore, the coolant and lubricant can be

  directed in the opposite direction To this end, the agent

  manager maybe injected under high pressure, direct-

  lie in the interstice 1% in the shape of a crescent, by a

  finger (not shown) entering a space 23 including

  caught between the front face 35 of the grinding spindle 4 and the opposite front face 30 of the part 1 The lubricating agent then passes into the rectification zone 16 and leaves the part 1 through the orifice 17 The advantage of this solution resides in the fact that the waste from the cutting zone 16 cannot reach the guiding and support zone of the part 1, but is discharged

  directly from part 1 through hole 17.

  In the device shown in Figures 3 and 4, the a-

  axial vance is effected by the grinding spindle 4 a (arrow 32) The part 1 is guided and held in the axial direction by a stop 40, represented by a bearing with hydrostatic axial load and provided on the front face 41 of the part 1 opposite the spindle 4 a On this front face 41, a circular groove 42, concentric with the nozzle 18 a, is supplied with pressurized fluid by a

supply line 43.

  The stop 40 and the nozzle 18 a are of a simple monobloc design; the pressurized fluid is the refrigerant

  and lubricant If only one line is provided for the

  ment in refrigerant and lubricant, the bearing

  hydrostatic stopper may have another form.

  In this case, a branch from the supply line

  mentation directs part of the circular groove

of the flow of the lubricant.

  Advancing the grinding spindle (arrow 39) and / or re-

  glage and the development of an optimal pressure for rec-

  tification can simply be ordered through the

  intermediate of the carrying stress appearing during machining The stress is then measured by a device 44, a manometer for example, then brought to an instrumentation device 45 connected to the control

in advance 46 of spindle 4 a.

  A particularly advantageous solution consists in di-

  set the grinding spindle 4 a against a fixed stop (not shown) The rod 5 a is then only introduced by a rapid movement in the bore 2, then the stop 40 is moved in the axis (arrow 47) during advancement Unit 45 is then connected to an advance device

(not shown) of the stop 40.

  As also shown in FIG. 3, the guide and support element constituted by the rod 5 a has at its two ends a bearing surface 7 a and / or 7 b, formed by a partial section 48 and / or 49 , on which the external diameter of

  the rod is reduced by rolling These bearing faces are

  kill at the ends of bore 2 They have on their periphery several grooves 50 distributed at a distance

  equal in the direction of the axis of the rod 5 a and / or of the bro-

  che 4 a and having a helical or oblique shape, so that each groove 50 constitutes a section of an imaginary helix As a result of this design,

  the bearing surfaces 7 a and 7 b have several super-

  sliding faces, ensuring particularly satisfactory guiding of the part 1 The direction of the grooves 50 being

  adapted to the direction of rotation of the rod 5 a, a pumping effect

  page reinforces the flow of the cooling and lubricating agent (arrow 51) Seen in a transverse direction relative to the axis of the spindle 56, the grooves 50 form an acute angle of about 150 with the latter. Furthermore, each groove a support surface 7 a is aligned with the

  corresponding groove on the other bearing surface 7 b.

  To ensure support and guidance without play of the part 1 on the rod 5 a, two motor rollers 9 b and 9 c (Figure 4) rest one behind the other on the periphery 8 of the part 1, so to partially overlap, seen in the axial direction of this same part 1 These rollers 9b and 9c are also mounted so that their

  contact lines 52 and 53 with the periphery 8 are symmetrical

  triques with respect to a longitudinal central plane 55 of the part 1, comprising the contact line 54 of the rod Sa and of the bore 2, and which the imaginary tangential planes of the contact lines 52 and 53 form with the contact line 54 an acute angle of about 600.

Claims (12)

Claims.   1 Rectification device for the finishing of a valve seat or of a seal face, notably a bicone ring of an injector, comprising a pin connected to a   grinding wheel, as well as a support and guiding element, ex-   centered in a finished bore of the part during the operation   machining ration and integral with the grinding wheel spindle, characterized in that the support and guide element (5) consists of a rod with a diameter smaller than that of the grinding wheel spindle, this rod supporting the   grinding wheel (6) at its free end (38) and being longer   as the bore (2) of the part, so that the spindle (4) is outside this same bore (2) in working position.   2 Device according to claim 1, characterized in that the diameter of the grinding wheel spindle (4) is at least double to four times that of the support element and guide (5).   3 Device according to one of claims 1 and 2, charac-   terized in that the support and guide element is cylindrical.   4 Device according to any one of claims 1 to   3, on which at least one drive roller is provided for the workpiece, characterized in that the axis (28) of the drive roller (9a) is oblique and forms with the workpiece axis   (29) an angle preferably of 2 to 5.   Device according to claim 4, characterized in that the angle (15) between the axes (2b, 29) of the roller   motor (9 a) and part (1) can be modified.   6 Device according to one of claims 4 and 5, charac-   terized in that two driving rollers (9 b, 9 c) are fitted   tees one behind the other so as to overlap, seen   in the direction of the axis of the part (1).   7 Device according to any one of claims 4 to   6, characterized in that the contact lines (52, 53) between the driving rollers (9 b, 9 c) and the periphery (8) of the part (1) are symmetrical with respect to a longitudinal median plane (55) of the part, comprising the contact line (54) of the support and guide element (5 a) and of the bore (2).   8 Device according to any one of claims 1 to   7, comprising a cooling system for bringing a coolant and lubricant under pressure into the cutting zone of the workpiece, via a orifice   this same part, characterized in that the system of re-   cooling has a nozzle (18) placed at a   distance from the orifice (17) of the part and preferably   rence aligned with this same orifice.   9 Device according to any one of claims 1 to   8, characterized in that a collector (21), provided for the cooling and lubricating agent, has the form of a   box with through holes (31, 32) for the bro-   che (4) and the part (1), in that the part (1) and the end   part (34) of the spindle oriented towards the workpiece   in the manifold (21), and in that a piece of cover   ment (20) is mounted between the part (1) and the end adjacent <(34) of the spindle.   Device according to any one of claims 1 to   9, characterized in that to the part (1) is added a   stop (40), preferably with hydrostatic thrust.   11 Device according to claim 10, characterized in that the stop (40) has a supply line (43) for the coolant and lubricant used during grinding 4 12 Device according to claim 11, characterized in that the line supply (43) is practically   parallel to the nozzle <18 a) and leads directly into - the recess (42) of the stop.   13 Device according to any one of claims 1   12, characterized in that the support and guide element (5 a) has at least two bearing surfaces (7 a,   7 b), separated by a certain axial distance.   14 Device according to claim 13, characterized in   that the bearing faces (7 a, 7 b) are located at the ends   tees of the support and guide element (5 a), and in that the external diameter of a portion (48, 49) between these two faces (7 a, 7 b) is less than that of the remaining part.   Device according to one of claims 13 and 14,   characterized in that the bearing faces (7 a, 7 b) have on their periphery several longitudinal grooves (50),   distributed at equal distance from each other.